Chapter 3: Organisation and the Digestive System

• Name three enzymes produced in the pancreas.

  amylase, protease, lipase
• What are enzymes?


  protein molecules that catalyse specific reactions in organisms
• Why are enzymes described as specific?

  each enzyme only catalyses a specific reaction, because the active site only fits together with certain substrates (like a lock and key)
• Describe the function of amylase

  to break down starch into glucose
• Where is amylase produced?

  salivary glands, pancreas, and small intestine
• Describe the function of proteases.


  to break down proteins into amino acids
• Where are proteases produced?

  stomach, pancreas, and small intestine
• Describe the function of lipases.


  to break down lipids into fatty acids and glycerol
• Where are lipases produced?

  pancreas and small intestine
• What are two factors that affect the rate of activity of an enzyme?

  temperature and pH
• What does denatured mean?

  shape of an enzyme’s active site is changed by high temperatures or an extreme pH, so it can no longer bind with the substrate
• Describe the effect of temperature on enzyme activity.

  as temperature increases, rate of reaction increases until it reaches the optimum for enzyme activity – above this temperature enzyme activity decreases and eventually stops
• Describe the effect of pH on enzyme activity.

  different enzymes have a different optimum pH at which their activity is greatest – a pH much lower or higher than this enzyme activity decreases and stops
• Why do different digestive enzymes have different optimum pHs?

  different parts of the digestive system have very different pHs – the stomach is strongly acidic, and the pH in the small intestine is close to neutral
• What is an organ system?

  a group of organs working together to perform a specific function